Question

find the sum of the following ap 2.7.12....to 10th term

Answer 1

First term (a) = 2
Common difference (d) = 7 - 2 = 5
Number of terms (n) = 10
Sum of first n terms of AP is given as
S = (n/2)[2a+(n-1)d]
S = (10/2)[{2×2}+{(10-1)×5}]
S = 5[4+(9×5)]
S = 5(4+45)
S = 5×49
S = 245

Answer 2

Hi Friend !!!!

Here is ur answer !!!

2,7,12,....

a = 2

d = 7-2 = 5

n = 10

a 10 = a+9d

= 2+9(5)

= 2+45

= 47

sn = n/2(a+an)

= 10/2 ( 2 + 47)

= 5(49)

= 245

Hope it helps u : )